Changes

For many years Ceres was listed as a planet, even after the [[asteroid]]s [[Pallas]], [[Juno]], and [[Vesta]] were discovered. With the discovery of yet more objects in what would later be known as the Asteroid Belt, Ceres was reclassified as an asteroid, the largest of all such bodies. But Ceres, unlike any other object in the asteroid belt, has a hydrostatic-equilibrium shape, characteristic of an object sufficiently massive that its self-gravity forces such a shape despite the rigid-body forces that normally hold a solid object's shape.

For many years Ceres was listed as a planet, even after the [[asteroid]]s [[Pallas]], [[Juno]], and [[Vesta]] were discovered. With the discovery of yet more objects in what would later be known as the Asteroid Belt, Ceres was reclassified as an asteroid, the largest of all such bodies. But Ceres, unlike any other object in the asteroid belt, has a hydrostatic-equilibrium shape, characteristic of an object sufficiently massive that its self-gravity forces such a shape despite the rigid-body forces that normally hold a solid object's shape.

In 2006, the discovery of [[Eris]] provoked a fresh look at all the bodies of the [[solar system]], and in particular what constituted a planet and what didn't. As a result of the debate, Eris and [[Pluto]], an object even smaller than Eris, were classed as [[dwarf planet]]s--a new classification with definite criteria. Ceres meets these criteria, and thus Ceres is considered a dwarf planet--the smallest of three known bodies of that class.

In 2006, the discovery of [[Eris]] provoked a fresh look at all the bodies of the [[solar system]], and in particular what constituted a planet and what didn't. As a result of the debate, Eris and [[Pluto]], an object even smaller than Eris, were classed as [[dwarf planet]]s—a new classification with definite criteria. Ceres meets these criteria, and thus Ceres is considered a dwarf planet—the smallest of three known bodies of that class.

== Composition ==

== Composition ==

Until today, the only observation of Ceres has been by telescope. Astronomers have inferred a remarkable number of the physical properties of Ceres from this observation, but wish to learn much more.

Until today, the only observation of Ceres has been by telescope. Astronomers have inferred a remarkable number of the physical properties of Ceres from this observation, but wish to learn much more.

On September 27, 2007, the [[Dawn mission]] began officially with the launch of Dawn, the first rocket probe to visit the asteroid belt. The Dawn craft carries an ion engine that it used on the second part of its journey after it makes rendezvous with [[Mars]]. Dawn entered orbit around the asteroid [[Vesta]] and then departed Vesta for the dwarf planet Ceres. It will reach Ceres in February of 2015 and will then become the first space probe ever to orbit two celestial bodies ''other than the earth.''<ref name=Dawn>"[http://dawn.jpl.nasa.gov/mission/index.asp Dawn Mission Overview]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]], March 31, 2008. Accessed June 2, 2008.</ref><ref name=Dawn2>Rayman, Marc D., Fraschetti, Thomas C., Raymond, Carol A., and Russell, Chrisopher T. "[http://dawn.jpl.nasa.gov/mission/Dawn_overview.pdf Dawn: A mission in development for exploration of main belt asteroids Vesta and Ceres]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]], April 5, 2006. Accessed June 2, 2008.</ref>

On September 27, 2007, the [[Dawn mission]] began officially with the launch of Dawn, the first rocket probe to visit the asteroid belt. The Dawn craft carries an ion engine that it used on the second part of its journey after it makes rendezvous with [[Mars]]. Dawn entered orbit around the asteroid [[Vesta]] and then departed Vesta for the dwarf planet Ceres. It will reach Ceres in February 2015 and will then become the first space probe ever to orbit two celestial bodies ''other than the earth.''<ref name=Dawn>"[http://dawn.jpl.nasa.gov/mission/index.asp Dawn Mission Overview]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]], March 31, 2008. Accessed June 2, 2008.</ref><ref name=Dawn2>Rayman, Marc D., Fraschetti, Thomas C., Raymond, Carol A., and Russell, Chrisopher T. "[http://dawn.jpl.nasa.gov/mission/Dawn_overview.pdf Dawn: A mission in development for exploration of main belt asteroids Vesta and Ceres]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]], April 5, 2006. Accessed June 2, 2008.</ref>

Walter T. Brown eagerly awaits the mass-spectrographic analysis of the water-vapor gushers on Ceres (see above). He predicts that analysis will show Ceres' water vapor rich in [[deuterium]], and at twice the concentration in the [[ocean]]s of [[Earth]]. This will provide further vindication of the Hydroplate Theory and leave another thorny matter for conventional astronomers to explain: what nuclear catastrophe could have occurred in the solar system to release enough neutrons to produce so much heavy [[hydrogen]], in [[comet]]s and asteroids?<ref name=examiner/>

Walter T. Brown eagerly awaits the mass-spectrographic analysis of the water-vapor gushers on Ceres (see above). He predicts that analysis will show Ceres' water vapor rich in [[deuterium]], and at twice the concentration in the [[ocean]]s of [[Earth]]. This will provide further vindication of the Hydroplate Theory and leave another thorny matter for conventional astronomers to explain: what nuclear catastrophe could have occurred in the solar system to release enough neutrons to produce so much heavy [[hydrogen]], in [[comet]]s and asteroids?<ref name=examiner/>